People who have spinal cord injury (SCI) experience an increase in bacterial infections. These infections always interfere with quality of life of the patient, frequently result in lost productivity due to hospitalization and, in the long term, cause significant morbidity. Bacteria that cause symptomatic urinary tract infections (UTI) can usually be found in the urine beforehand. However, not all bacteria present in the bladder of people with SCI lead to UTI. Bacteria usually colonize the bladder of most SCI patients who rely upon indwelling catheterization, and of many others who use other methods for bladder management. Some of these bacteria result in UTI while other bacteria colonize the bladder without causing overt symptoms of infection. In the SCI patient group, seemingly benign bacterial colonization of the bladder is often left untreated as it may offer some protection against more harmful bacteria. One such seemingly benign bacterium, called E. coli 83972, was identified previously. Several studies revealed that E. coli 83972 was able to persist in the human bladder for extended periods, up to four years (8 to 12 months on average), after it was experimentally implanted. SCI test subjects who maintained bladder colonization with E. coli 83972 remained essentially free from symptoms of bladder infection for as long as E. coli 83972 was present. They remained essentially free of symptoms even when other bacteria were present in the urine together with E. coli 83972. UTI is an almost universal occurrence among persons with SCI. It is associated with large personal and monetary cost to the patient and to society. As a consequence, study of the impact of deliberate bladder colonization with E. coil 83972 on the occurrence of symptomatic UTI has the potential for improving the quality of life of SCI patients and decreasing the cost of health care. The proposed study consists of a single aim that deals with the efficacy of this method in SCI patients. The PIs propose a prospective, randomized, double-blind placebo-controlled multicenter trial to evaluate the clinical efficacy of this innovative therapeutic protocol. [unreadable] [unreadable]